1. Field of the Invention
The present invention relates to a boarding bridge and, more particularly, pertains to a boarding bridge intended primarily for use with small aircraft or the like.
2. Description of the Prior Art
Conventional passenger boarding bridges for large jet aircraft are well known in the art as illustrated by U.S. Pat. No. 3,123,167 issued to Lichti on Mar. 3, 1964 and U.S. Pat. No. 3,317,942 issued to Wollard et al. on May 9, 1967. Typically, such passenger boarding bridges comprise at least two telescopic bridge sections mounted at an elevation above ground level for bridging the space between a doorway in the fuselage of a large aircraft and the second floor in an airport terminal building. The telescoping bridge may be supported by a vertically extensible and contractible, self-propelled, steerable vehicle which is also operational to extend and contract the telescoping bridge. Alternatively, conventional telescoping boarding bridges may be displaced along an elevated horizontal trackway by operation of a cylinder mounted at a first end thereof to a rear fixed bridge section and at opposed end thereof to a front telescoping bridge section of the boarding bridge.
Such conventional passenger boarding bridges are relatively large in size and height and thus they are not generally practicable for use with small aircraft such as commuter aircraft. Moreover, large aircraft have doors that open to one side, whereas small or commuter aircraft are generally equipped with doors that swing down and have steps and handrails integrally set on the back thereof. Thus conventional passenger boarding bridges are not well adapted to mate with the fuselage of commuter aircraft since they cannot fit around the doorways thereof.
Some characteristics are peculiar to commuter aircraft, such as the location of the passenger door which is relatively close to the wings, requiring an optimization of the extension and retraction distance to allow sufficient aircraft wing clearance during parking and departure manoeuvres of a given commuter aircraft.
Accordingly, various solutions have been proposed so that passengers, enplaning or deplaning from small aircraft might avoid walking directly on the airport tarmac and to protect them from the elements such as rain, hail, sleet, snow and wind. For instance, U.S. Pat. No. 5,524,318 issued to Thomas on Jun. 11, 1996 discloses an aircraft loading adapter for bridging between a small aircraft and a conventional boarding bridge ordinarily employed with standard size aircraft. The aircraft loading adapter comprises a pair of independent actuable vertical supports which extend upwardly from a mobile platform and connect at an upper end thereof with the underside of a rear telescoping bridge section of an enclosed bridge structure to provide vertical adjustment of the ends of the latter. The rear end of the rear telescoping bridge section is provided with a curved surface which is conformed to the front end of a conventional boarding bridge and is pivoted about a horizontal axis. The bridge structure further includes a front telescoping bridge section having a front extension which is adapted to mate with the fuselage of a small aircraft. In operation, each vertical support is independently activated to align the front extension of the front telescoping bridge section with the entry/exit hatch of the small aircraft. According to a second embodiment, one of the actuable vertical supports is replaced by a vertical supporting member which is pivotally connected at an upper end thereof to the underside of the rear telescoping bridge section.
It is also know to provide the front end of a boarding bridge with extensible and retractable forward portions for covering the aircraft doorways. U.S. Pat. No. 3,588,934 issued to Van Marle on Jun. 29, 1971 discloses a conventional boarding bridge having an end section which includes side members pivotally mounted for rotation about an axis coinciding with the front lower edge of the section. Hydraulic jacks are provided to pivot the side members. A roof is secured to the upper ends of the side members for movements therewith.
Basically, the extensible and retractable forward portion described in the above-mentioned patent is intended for sheltering the doorway of conventional aircraft and is thus not well adapted for covering the door opening and stairs of a small aircraft.